<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CssForButtonBorder</title>
    <style>
        button
        {
            background-color: #EAF2D3;
            color: #000;
            text-align: center;
            text-decoration: none;
            font-size: 16px;
            margin: 4px 2px;
            padding: 20px 50px;

        }
        .green
        {
            background-color: #fff9f9;
            border: 2px solid #6eb8b5;
            color: green;
        }

        .red
        {
            background-color: #eeeee3;
            border: 2px solid #6eb8b5;
            color: red;
        }

        .blue
        {
            background-color: #f9f4ff;
            border: 2px solid #6eb8b5;
            color: blue;
        }

        .black
        {
            background-color: #fff9f9;
            border: 2px solid #6eb8b5;
            color: black;
        }
    </style>
</head>
<body>

<button class="green">
    绿
</button>
<br>
<button class="blue">
    蓝
</button>
<br>
<button class="red">
    红
</button>
<br>
<button class="black">
    黑
</button>

</body>
</html>